Drug interactions
Pirbuterol + Timolol
Severity: Major
Pirbuterol and Timolol: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Timolol is a non-selective beta-blocker that blocks the beta-2 receptors that pirbuterol stimulates, so bronchodilation may be reduced and asthma or COPD symptoms may worsen. Even ophthalmic timolol can be absorbed enough to cause bronchospasm in susceptible patients.
What this interaction means in plain words
Pirbuterol and Timolol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Pharmacodynamic antagonism at beta-2 adrenergic receptors by non-selective beta-blockade.
What to do
Avoid timolol in patients who depend on pirbuterol for airway disease; use a cardioselective agent or a non-beta-blocker alternative if one is needed. Monitor respiratory status if the combination cannot be avoided.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Timolol
- Acebutolol + Timolol Major
- Albuterol + Timolol Major
- Aldesleukin + Timolol Major
- Amifostine + Timolol Major
- Amiodarone + Timolol Major
- Arformoterol + Timolol Major
Frequently asked questions
Can I take Pirbuterol with Timolol?
MediHelp rates the interaction as major. Pirbuterol and Timolol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Timolol is a non-selective beta-blocker that blocks the beta-2 receptors that pirbuterol stimulates, so bronchodilation may be reduced and asthma or COPD symptoms may worsen. Even ophthalmic timolol can be absorbed enough to cause bronchospasm in susceptible patients.
How serious is the interaction between Pirbuterol and Timolol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid timolol in patients who depend on pirbuterol for airway disease; use a cardioselective agent or a non-beta-blocker alternative if one is needed. Monitor respiratory status if the combination cannot be avoided.
What other medicines interact with Timolol?
MediHelp also lists interactions of Timolol with, for example, Acebutolol, Albuterol, Aldesleukin. The full list is on the Timolol page.
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